The FD-NEMD approach has been applied extensively by [1]} et al., with the body force coupling to particle variables such as the mass or the charge [2]}.
In the case of diffusion, Maginn  et al. [3]} performed NEMD using a color field, in which particles are assigned color charges according to their chemical identity. In this way, they replaced the chemical potential gradient by a color force of equal magnitude but opposite sign.
